Green synthesis and characteristics of Ag-ZnO doped nanoparticles utilizing plant extracts as reducing agents

ZnO and Ag-ZnO nanoparticles have been successfully synthesized using a simple green method, in which extracts of pomelo peel, bear’s breech leaf, and fresh lime act as effective reducing and stabilizing agents. This approach is not only environmentally friendly and cost-effective, but it also allows for adjustments to the material’s properties through variations in calcination temperature and silver doping concentration. The synthesized nanoparticles were comprehensively characterized by various physicochemical techniques. The resulting nanoparticles depicted a diverse length range from 15.1 to 20.2 nm. XRD and XPS analyses confirmed the stable wurtzite structure of ZnO and, concurrently, recognized the presence of silver in both metallic and ionic states within the crystal lattice. The doping of Ag led to a contraction in crystallite grains, caused minor shifts in diffraction peaks, decreased the bandgap energy, and extended the light absorption range into the visible region, as evidenced by UV-VIS DRS. These were corroborated by experimental results demonstrating the high tetracycline degradation efficiency of all samples. Specifically, the 1.5% Ag-doped sample exhibited a high degradation rate (up to 91.21%) after being exposed to Philips’ white LED for 30 minutes, and the efficiency further increased to 92.06% after 180 minutes of continuous illumination. The use of this LED lamp is energy-efficient, and its operating wavelength within the visible light spectrum enhances its practical applicability. This is because the obtained results can still be applied under artificial lighting conditions, as well as utilizing natural solar energy. Antibacterial tests showed that the 1.5% Ag-doped ZnO sample had the ability to suppress E. coli bacteria with nearly complete antibacterial efficacy at a concentration of 500 μg mL -1 (corresponding to Ag content of approximately 7.5 μg mL -1 . This finding asserted the potential application of green-synthesized Ag–ZnO nanoparticles in the fields of antibacterial agents and photocatalysis, while also promoting a sustainable and reliable approach to functional materials manufacturing.